Bump min supported PHP ver to 7.0 (#52982)

* Bump plugin's "Requires PHP"
* Bump PHPCS testVersion
* Bump previous WP version CI job

.github/workflows/unit-test.yml

@@ -97,7 +97,7 @@ jobs:
                 wordpress: [''] # Latest WordPress version.
                 include:
                     # Test with the previous WP version.
-                    - php: '5.6'
+                    - php: '7.0'
                       wordpress: ${{ needs.compute-previous-wordpress-version.outputs.previous-wordpress-version }}
                     - php: '7.4'
                       wordpress: ${{ needs.compute-previous-wordpress-version.outputs.previous-wordpress-version }}

gutenberg.php

@@ -4,7 +4,7 @@
  * Plugin URI: https://github.com/WordPress/gutenberg
  * Description: Printing since 1440. This is the development plugin for the block editor, site editor, and other future WordPress core functionality.
  * Requires at least: 6.1
- * Requires PHP: 5.6
+ * Requires PHP: 7.0
  * Version: 16.3.0
  * Author: Gutenberg Team
  * Text Domain: gutenberg

phpcs.xml.dist

@@ -2,7 +2,8 @@
 <ruleset name="WordPress Coding Standards for Gutenberg Plugin">
 	<description>Sniffs for WordPress plugins, with minor modifications for Gutenberg</description>
 
-	<config name="testVersion" value="5.6-"/>
+	<!-- Check for cross-version support for PHP 7.0 and higher. -->
+	<config name="testVersion" value="7.0-"/>
 	<rule ref="PHPCompatibilityWP">
 		<include-pattern>*\.php$</include-pattern>
 	</rule>